Lifting columns for medical devices can be found, for instance, in operating tables, transporters for storage areas, or supply vehicles. The demands on such lifting columns will be explained below by way of the example of a surgical table.
Before and during surgery on a patient lying on a patient positioning surface of an operating table, the patient positioning surface is typically brought into a position which allows for performing operations on the patient. In this context, it may be suitable to swivel the patient positioning surface around a horizontal axis at a comparatively large angle. The height of the patient positioning surface of the operating table should be suitably adjustable. The operating table can also be adjusted such that patient positioning surface is at relatively low elevations, which typically involves a space-saving structure of the operating table column.
Also during the operation, it may be appropriate to change the position, and particularly the height, of a patient. The components serving the change of position should therefore function reliably. Specifically, the components are guided in a sufficiently precise manner so as to make possible height adjustments without the tilting of the components. Moreover, the movable parts of the operating table tend to wear out, and should therefore be formed to be relatively stable and durable.
Typically, the components serving for height adjustments are lifting columns, in which multiple column elements slide along their mutual longitudinal axis inside each other. Since the inner surface of the column elements are not easy to access for machining purposes, they are often executed in a less precise, and in particular, in a less smooth manner They are therefore less suitable for serving as slide surfaces than the more easily machinable outer surfaces of the column elements.
From document DE 202007014791 U1, a lifting column with an inner profile and an outer profile is known, which are movable relative to each other in their mutual longitudinal direction. Between the two profiles there are slide elements, serving as separators. Each of the slide elements is mounted on one of the profiles, and slides along the respective other profile. The respective slide element consists of two parts, and is formed in the shape of a wedge. The two slide elements are movable relative to each other by an adjusting screw, and therefore have a variable total thickness. A disadvantage of these slide elements is that upon assembly, they are fixed in a laborious manner inside the respective profile. Furthermore, after a certain amount of use time, these slide elements are readjusted, which typically involves an additional laborious operation.